<!DOCTYPE html>
<svg>
  <clipPath id="clip" clip-path="url(#nosuchclip)">
    <rect width="100" height="100"/>
  </clipPath>
  <mask id="mask"></mask>
  <rect width="300" height="100" fill="red"/>
  <rect width="100" height="100" fill="green" clip-path="url(#nosuchclip)"/>
  <rect transform="translate(100 0)" width="100" height="100" fill="green" clip-path="url(#mask)"/>
  <rect transform="translate(200 0)" width="100" height="100" fill="green" clip-path="url(#clip)"/>
</svg>
